Re-imprisonment rates are displayed in Table 5, prior to controlling for relevant
factors, for the public and private adult male releases within each of the
six methods of identifying the two types of inmates. Overall, public adult
male inmates have slightly higher re-imprisonment rates; however, only four
of the possible thirty-six differences are higher than 2.0% (Groups A2 and
C1 for thirty-six months, Group A2 for 48 months, and Group A1 for 56 months)
and none are over 3.0%. Additionally, none of these re-imprisonment rate differences
between public and private adult male inmates are statistically significant
at the p<.05 level.

None of the recidivism rate differences were statistically
significant at the p<.05 level (Wilcoxon Test).
* No comparison group had estimates for longer than 56 months.

Table 6 displays the distributions of the private and public adult male inmates
on the eighteen variables used in the final survival models to answer the question
whether recidivism rates differ between the two groups. The demographic characteristics
of age at release, race, and ethnicity, across the public and private adult
male inmates are virtually the same. In contrast, public adult male inmates
are somewhat more likely to have more prior recidivism events than private
inmates (average: public = 1.2; private = 1.1) and are considerably more likely
to be released as close custody inmates (public = 17.0%; private = 1.1%). Public
adult male inmates are also much more likely to spend longer lengths of time
in prison (average months: public = 31.3; private = 16.8) and have more disciplinary
problems while in prison (average disciplinary reports: public = 2.9; private
= 0.8). The median TABE score for public adult male inmates is slightly lower
than for private adult male inmates (7.1 versus 7.6) and they are considerably
more likely to be released to some form of post-prison supervision (36.9% versus
23.4%). In terms of their most serious crime type, public adult male inmates
are more likely to have committed a homicide, sex/lewd offense, or a robbery
than private inmates. However, the two groups are very similar in terms of
their total number of convictions for property, drug, and weapons offenses.

Table 6:
Adult Males -
Descriptive Statistics of Public and Private Inmates
Treatment and Control Group Definition B1

Public

Private

Total

Total Cases

58,342

2,993

61,335

Age at Release

Under 18

10

0.0%

0

0.0%

10

18 to 24

7,934

13.6%

387

12.9%

8,321

25 to 34

24,697

42.3%

1,270

42.4%

25,967

35 to 49

22,940

39.3%

1,173

39.2%

24,113

50 to 59

2,211

3.8%

138

4.6%

2,349

60+

550

0.9%

25

0.8%

575

Average

34.0

34.2

Race – Black

33,891

58.1%

1,753

58.6%

35,644

Hispanic

2,995

5.1%

161

5.4%

3,156

Prior Recidivism Events **

0

25,404

43.5%

1,425

47.6%

26,829

1

14,554

24.9%

688

23.0%

15,242

2

8,702

14.9%

424

14.2%

9,126

3

5,224

9.0%

240

8.0%

5,464

4

2,676

4.6%

125

4.2%

2,801

5 +

1,782

3.1%

91

3.0%

1,873

Average

1.2

1.1

Custody Low **

28,206

48.3%

1,744

58.3%

29,950

Custody High **

9,944

17.0%

33

1.1%

9,977

Months in Prison **

1-12

15,193

26.0%

1,455

48.6%

16,648

13-24

16,737

28.7%

1,004

33.5%

17,741

25-36

9,452

16.2%

323

10.8%

9,775

37-48

5,781

9.9%

116

3.9%

5,897

49-60

3,556

6.1%

55

1.8%

3,611

61+

7,623

13.1%

40

1.3%

7,663

Average

31.3

16.8

Total Disciplinary Reports **

0

28,491

48.8%

2,139

71.5%

30,630

1

9,896

17.0%

458

15.3%

10,354

2

5,129

8.8%

169

5.6%

5,298

3 to 6

7,703

13.2%

158

5.3%

7,861

7 or More

7,123

12.2%

69

2.3%

7,192

Average

2.9

0.8

Last TABE Score **

1-3.9

11,110

19.0%

489

16.3%

11,599

4-8.9

30,535

52.3%

1,484

49.6%

32,019

9-11.9

9,215

15.8%

603

20.1%

9,818

12-12.9

7,482

12.8%

417

13.9%

7,899

Median

7.1

7.6

Supervision – Yes **

21,541

36.9%

699

23.4%

22,240

Most Serious – Homicide **

3,016

5.2%

50

1.7%

3,066

Most Serious - Sex/Lewd **

5,247

9.0%

179

6.0%

5,426

Most Serious – Robbery **

12,122

20.8%

456

15.2%

12,578

Most Serious - Other Violent

14,857

25.5%

806

26.9%

15,663

Most Serious – Burglary *

11,723

20.1%

653

21.8%

12,376

Total Property Crimes (Average)

1.1

1.1

Total Drug Crimes (Average) **

1.1

1.4

Total Weapons Crimes (Average)

0.2

0.2

Significance levels based on T-Tests when averages are
displayed and
Chi-Square when
they are not.
* Significant at p<.05, ** Significant at p<.01.

The differences described on many of the control variables for the public
and private adult male inmates clearly indicates the need to hold these factors
constant when evaluating whether differences in recidivism probabilities exist
between the two groups. Public adult male inmates have higher rates of prior
recidivism rates, close custody, and disciplinary infractions, as well as lower
TABE scores. These characteristics are all associated with a higher likelihood
of recidivism. In contrast, private adult male inmates have shorter lengths
of stay in prison and are less likely to have post-prison supervision, which
are predictive of higher recidivism rates.

To determine whether the private prison experience for adult males affects
their likelihood of recidivism in terms of re-offense or re-imprisonment rates,
we employed multivariate survival models which control, or hold constant, the
effects of other variables known to influence recidivism rates. Table 7 displays
these results and clearly shows there are no statistically significant differences
in re-offense or re-imprisonment rates between public and private adult male
inmates using any of six methods for quantifying private prison experience.
Using the re-offense recidivism measure, all the relationships between the
type of prison and reoffense indicate that private inmates are slightly more
likely to recidivate than public adult male inmates (MLE’s = .01 to .04)
but these differences are not statistically significant. Using the reimprisonment
recidivism measure, all the relationships between the type of prison and this
recidivism measure are very slight (-.01 to +.01) and, again, not statistically
significant.